GenerateCubesFromLabels
VTKEx/Cxx/Medical/GenerateCubesFromLabels
Description¶
Sometimes it is helpful to view the results of a segmentation without any post processing. This example converts the point data from a labeled volume into cell data. The surfaces are displayed as vtkPolydata. If you want to created smoothed polydata models from your segmented volumes, see the example GenerateModelsFromLabels. The input volume must be in MetaIO format.
Usage: GenerateCubesFromLabels FullHead.mhd StartLabel EndLabel
where
InputVolume is a meta file containing a 3 volume of discrete labels.
StartLabel is the first label to be processed
EndLabel is the last label to be processed
NOTE: There can be gaps in the labeling. If a label does not exist in the volume, it will be skipped.
Note
This original source code for this example is here.
Question
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Code¶
GenerateCubesFromLabels.cxx
//
// GenerateCubesFromLabels
// Usage: GenerateCubesFromLabels InputVolume Startlabel Endlabel
// where
// InputVolume is a meta file containing a 3 volume of
// discrete labels.
// StartLabel is the first label to be processed
// EndLabel is the last label to be processed
// NOTE: There can be gaps in the labeling. If a label does
// not exist in the volume, it will be skipped.
//
//
#include <vtkMetaImageReader.h>
#include <vtkImageAccumulate.h>
#include <vtkImageWrapPad.h>
#include <vtkMaskFields.h>
#include <vtkThreshold.h>
#include <vtkTransformFilter.h>
#include <vtkGeometryFilter.h>
#include <vtkSmartPointer.h>
#include <vtkTransform.h>
#include <vtkImageData.h>
#include <vtkPointData.h>
#include <vtkCellData.h>
#include <vtkUnstructuredGrid.h>
#include <vtkRenderer.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkPolyDataMapper.h>
int main (int argc, char *argv[])
{
if(argc < 4)
{
std::cout << "Usage: " << argv[0] << " InputVolume StartLabel EndLabel" << std::endl;
return EXIT_FAILURE;
}
// Define all of the variables
unsigned int startLabel = atoi(argv[2]);
unsigned int endLabel = atoi(argv[3]);
// Generate cubes from labels
// 1) Read the meta file
// 2) Convert point data to cell data
// 3) Convert to geometry and display
vtkSmartPointer<vtkMetaImageReader> reader =
vtkSmartPointer<vtkMetaImageReader>::New();
reader->SetFileName(argv[1]);
reader->Update();
// Pad the volume so that we can change the point data into cell
// data.
int *extent = reader->GetOutput()->GetExtent();
vtkSmartPointer<vtkImageWrapPad> pad =
vtkSmartPointer<vtkImageWrapPad>::New();
pad->SetInputConnection(reader->GetOutputPort());
pad->SetOutputWholeExtent(extent[0], extent[1] + 1,
extent[2], extent[3] + 1,
extent[4], extent[5] + 1);
pad->Update();
// Copy the scalar point data of the volume into the scalar cell data
pad->GetOutput()->GetCellData()->SetScalars(
reader->GetOutput()->GetPointData()->GetScalars());
vtkSmartPointer<vtkThreshold> selector =
vtkSmartPointer<vtkThreshold>::New();
selector->SetInputArrayToProcess(0, 0, 0,
vtkDataObject::FIELD_ASSOCIATION_CELLS,
vtkDataSetAttributes::SCALARS);
selector->SetInputConnection(pad->GetOutputPort());
selector->ThresholdBetween(startLabel, endLabel);
selector->Update();
// Shift the geometry by 1/2
vtkSmartPointer<vtkTransform> transform =
vtkSmartPointer<vtkTransform>::New();
transform->Translate (-.5, -.5, -.5);
vtkSmartPointer<vtkTransformFilter> transformModel =
vtkSmartPointer<vtkTransformFilter>::New();
transformModel->SetTransform(transform);
transformModel->SetInputConnection(selector->GetOutputPort());
vtkSmartPointer<vtkGeometryFilter> geometry =
vtkSmartPointer<vtkGeometryFilter>::New();
geometry->SetInputConnection(transformModel->GetOutputPort());
vtkSmartPointer<vtkPolyDataMapper> mapper =
vtkSmartPointer<vtkPolyDataMapper>::New();
mapper->SetInputConnection(geometry->GetOutputPort());
mapper->SetScalarRange(startLabel, endLabel);
mapper->SetScalarModeToUseCellData();
mapper->SetColorModeToMapScalars();
vtkSmartPointer<vtkActor> actor =
vtkSmartPointer<vtkActor>::New();
actor->SetMapper(mapper);
vtkSmartPointer<vtkRenderer> renderer =
vtkSmartPointer<vtkRenderer>::New();
vtkSmartPointer<vtkRenderWindow> renderWindow =
vtkSmartPointer<vtkRenderWindow>::New();
renderWindow->AddRenderer(renderer);
vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor =
vtkSmartPointer<vtkRenderWindowInteractor>::New();
renderWindowInteractor->SetRenderWindow(renderWindow);
renderer->AddActor(actor);
renderer->SetBackground(.1, .2, .3);
renderWindow->Render();
renderWindowInteractor->Start();
return EXIT_SUCCESS;
}
CMakeLists.txt¶
cmake_minimum_required(VERSION 3.3 FATAL_ERROR)
project(GenerateCubesFromLabels)
find_package(VTK COMPONENTS
vtkvtkCommonCore
vtkvtkCommonDataModel
vtkvtkCommonTransforms
vtkvtkFiltersCore
vtkvtkFiltersGeneral
vtkvtkFiltersGeometry
vtkvtkIOImage
vtkvtkImagingCore
vtkvtkImagingStatistics
vtkvtkInteractionStyle
vtkvtkRenderingContextOpenGL2
vtkvtkRenderingCore
vtkvtkRenderingFreeType
vtkvtkRenderingGL2PSOpenGL2
vtkvtkRenderingOpenGL2 QUIET)
if (NOT VTK_FOUND)
message("Skipping GenerateCubesFromLabels: ${VTK_NOT_FOUND_MESSAGE}")
return ()
endif()
message (STATUS "VTK_VERSION: ${VTK_VERSION}")
if (VTK_VERSION VERSION_LESS "8.90.0")
# old system
include(${VTK_USE_FILE})
add_executable(GenerateCubesFromLabels MACOSX_BUNDLE GenerateCubesFromLabels.cxx )
target_link_libraries(GenerateCubesFromLabels PRIVATE ${VTK_LIBRARIES})
else ()
# include all components
add_executable(GenerateCubesFromLabels MACOSX_BUNDLE GenerateCubesFromLabels.cxx )
target_link_libraries(GenerateCubesFromLabels PRIVATE ${VTK_LIBRARIES})
# vtk_module_autoinit is needed
vtk_module_autoinit(
TARGETS GenerateCubesFromLabels
MODULES ${VTK_LIBRARIES}
)
endif ()
Download and Build GenerateCubesFromLabels¶
Click here to download GenerateCubesFromLabels and its CMakeLists.txt file. Once the tarball GenerateCubesFromLabels.tar has been downloaded and extracted,
cd GenerateCubesFromLabels/build
If VTK is installed:
cmake ..
If VTK is not installed but compiled on your system, you will need to specify the path to your VTK build:
cmake -DVTK_DIR:PATH=/home/me/vtk_build ..
Build the project:
make
and run it:
./GenerateCubesFromLabels
WINDOWS USERS
Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.